In the present paper we consider the elements na, a and as, which combine with the finite verb and give rise to a variety of modal readings, such as future, subjunctive, etc. On the basis of their distributional similarities and differences, we argue that the elements under consideration are situated in the left periphery and fall into two categories: a and as have a verbal property, while na has a locative one which also underlies its deictic use. This approach allows us to get a better understanding of their current syntactic status, and also has certain implications regarding their diachronic development (e.g. 'grammaticalization'). Our analysis is consistent with the view that there is no syntactic category 'particle' (Zwicky 1985).